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JOHN D. 'GllllNEllERG AND SAMUEL H. GILBERT, OF SPRING MILLS,'NEW

JERSEY,

Letters Patent No. 75,898, dated ZlIm'ch 24, 1868.

IMPROVEMENT IN COATING METALS.

TO ALL WHOM IT MAY CONCERN:

Be it known that we, Jon: D. Guiinununc and Smear. X I. GILBERT, both of Spring Mills, -in the county of Camden, and State of New Jersey, have invented a new and useful Improvement in Articles of Metal; and we do hereby declare the following to be a clear and exact description of the nature thereof, suflicient to enable others skilled in the art to which ourinventionappertains to fully understand and use the same.

'H'itherto it has been customary to cover shept iron and copper, and probably other hard metals, with tin or alloys, by dipping the former in acid, and tliediu a solution of the tin or alloy. The disadvantage of this process is that-only small sheets of metal can thus be coated or plated, because, in preparing large sheets, it was found that a considerable portion of the surplus covering or plating would harden before it had run off from the lower end of'the sheets, so that only part of said. sheets would possess the proper thickness or surface.

Our invention is specially intended to remedy this. We have found that long or large sheets of-mctal can be uniformly coated or plated in a simple manner, so that an article of metal is produced which possesses all the advantages of pure tin, and at a much less expense.

:If' the sheets of tin or alloy are spread or laid upon sheets of hard metal so as to entirely overlap them, and the two sheets be subjected to rolling under a heavy pressure, the friction thereby will heat the metals in passing through the rolls, and cause them to unitefirmly and with a uniform surface, so as to produce a superior article of metal.

In carrying out our invention, we take blocks or sheets of any of the aforementioned hard metals, and

rollthem, in a cold or heated state, until they assume a certain thickness. We then make an alloy of either of the following One quarter tin, one quarter copper, and one half load, more or less; or six parts tin, one, antimony; or fifty parts tin, four, antimony, one, bismuth; or fourteen parts tin, one twentyeighth partzine or copper, or one half of each of the latter ones; or pure tin, alloyed with as much of oncof the above-named metals, or any other metal which will give it more stiffness and durability than it has in its natural state; or we use pure tin itself.

A block of the tin, or tin or other alloy, is new cast in a mould of suitable size, which block isthon passed through highly-polished rollers, sons to be reduced to a proper thickness to answer the purpose of common plating. The thickness may vary from one to thirty-five per cent. of the original thickness of the block or sheet of hard metal selected.

The strips thus produced are then severally spread or laid upon a smooth, lerol table. One of the afore mentioned blocks or sheets of-hard metal is how laid upon one of the strips of tin or alloy, which strip is then lapped over the former, so as to entirely cover it. Care must be taken to rub it smoothly, in order to prevent tho formation of air-blisters or wrinkles. The compound sheet or block thus constituted is now passed between highly-polished rollers under heavy pressure, whereby the metals become quite hot in passing through, thus causing them to firmly unite, and evenly, in one solid sheet, having either the tin or alley, or other metal, for the outer coating.

Instead of the above process, we prepare a solution of one pound of muriato or nitrate of tin, and ten gallons (or eighty pounds) water, (98 Fahrenhcit,) more or less. Into this bath we dip the desired sheet ofhard metal for the space of five to twenty minutes, more or less, when the sheet will be found sufiicicntly covered with pure tin. 'It may then be polished orrubbed bright with soft cloth or leather.

It will be found that steel or iro'ncoated with tin or alloy can be used for cooking-utensils, and for every article in which sheet tin is employed. The surface being entirely uniform, it cannot be affccted'by dampness, and thus serves to prevent rust.

Our process prevents oxidation or corrosion in zinc. We can produce very large sheets theroof,when, by the process now employed, it can only be produced in small pieces. For lining bath-tubs, water-cisterns, and the like, our zinc will be found invaluable.

For photographic and lithographic purposes, we i'nterposc between the sheets of covered or plated zinc suitable pieces of-tissueer other paper, muslin, or any equivalent fabric, and then subject them to another uses 2 pressure; or we pass the metal between rollers having a slightly-roughened surface, so that the impression of the paper, fabric, or rollers willbe imparted to the metal, and cause its surface to assume a certain roughness necessary for photographic, lithographic, printing, or any other ornamental purposes.

The uses to which our invention can be applied are numerous; generally speaking, to all purposes requiring stifi' metal, which shall neither corrode, crack, nor be afieeted by heat or cold, and also topossess the advantages of pure tin. I 7 We are aware that hard metals have been eoatcdor plated with tin or alloys by an old and well-known process; this we do not, therefore, elainz. Having thus described our invention what we claim as new, and desire to secure by Letters Patent, isi The within mode of coating or plating hard metals, substantially as described. To the above, we have signed our nazxtcs, this 11th day of January, 1867.

JOHN D. GRUNEBERG, SAMUEL H. GILBERT.

Witnesses:

JOHN A; WIEoEnsHEIM, WM. A. WIEDERSHEIM. 

